JP5810915B2 - Biaxially oriented polyester film for molding - Google Patents

Description

  The present invention relates to a biaxially oriented polyester film that is particularly suitable for use in molding.

  In recent years, due to increasing environmental awareness, there has been an increasing demand for solventless painting, plating replacement, etc. for building materials, automobile parts, mobile phones, electrical appliances, etc., and the introduction of decoration methods using films is progressing.

  Several proposals have been made as molding polyester films used in such decoration methods. For example, a molding polyester film that defines a specific molding stress at room temperature has been proposed (see, for example, Patent Document 1).

  In addition, a molding polyester film in which a molding stress and a storage elastic modulus at a specific temperature are defined has been proposed (see, for example, Patent Document 2).

  Furthermore, a polyester film for molding that defines a storage elastic modulus in a wide temperature range has also been proposed (see, for example, Patent Document 3).

JP 2001-347565 A JP-A-2005-290354 JP 2008-162220 A

  However, the film described in Patent Document 1 is not necessarily designed as a film that is not always sufficiently moldable and is also considered in terms of dimensional stability.

  In addition, the film described in Patent Document 2 is a film that is inferior in processability due to insufficient dimensional stability in the vicinity of 80 ° C., which is the processing temperature of the film.

  In addition, the film described in Patent Document 3 exhibits a low storage elastic modulus in a wide temperature range, and thus is excellent in moldability, but is still not sufficient in terms of dimensional stability and exhibits satisfactory heat resistance. is not.

  An object of the present invention is to eliminate the above-described problems of the prior art. That is, an object of the present invention is to provide a biaxially oriented polyester film for molding which is excellent in moldability, dimensional stability, heat resistance, and appearance, and can be suitably used for various molded members after being subjected to molding processing.

The gist of the present invention for solving the problems is that the stress at 100% elongation (F100 value) in the film longitudinal direction and the width direction at 150 ° C. is 5 MPa or more and 60 MPa or less, respectively, and the film longitudinal direction at 80 ° C. And a storage elastic modulus in the width direction of 2001 MPa to 3000 MPa, respectively, and a biaxially oriented polyester film for molding having a storage elastic modulus in the film longitudinal direction and width direction at 180 ° C. of 41 MPa to 400 MPa.

  Since the biaxially oriented polyester film for molding of the present invention has a low molding stress in the molding temperature range, various molding methods such as vacuum molding, pressure molding, vacuum pressure molding, in-mold molding molded by injection resin pressure, etc. Since the storage modulus in the processing temperature range is in a specific range, it has excellent dimensional stability in processing processes such as coating, laminating, printing, and vapor deposition. It can be decorated by other means, and since it has a high storage elastic modulus in a high temperature region, it has excellent heat resistance, excellent surface properties even after molding, and excellent color tone, so the appearance is good For example, it can be suitably used for decorating molded members such as building materials, mobile devices, electrical products, automobile parts, and gaming machine parts.

  The polyester constituting the biaxially oriented polyester film for molding of the present invention is a general term for polymer compounds in which main bonds in the main chain are ester bonds. The polyester resin can be usually obtained by polycondensation reaction of dicarboxylic acid or its derivative with glycol or its derivative.

In the present invention, from the viewpoint of moldability, appearance, heat resistance, dimensional stability and economy, 60 mol% or more of the glycol units constituting the polyester is a structural unit derived from ethylene glycol, and 60 mol% of the dicarboxylic acid unit. The above is preferably a structural unit derived from terephthalic acid. Here, the dicarboxylic acid unit (structural unit) or the diol unit (structural unit) means a divalent organic group from which a portion to be removed by polycondensation has been removed. Dicarboxylic acid unit (structural unit) represented by: —CO—R—CO—
Diol unit (structural unit): —O—R′—O—
(Where R and R ′ are divalent organic groups)
The same applies to the meaning of units (structural units) of trivalent or higher carboxylic acids such as trimellitic acid units and glycerin units, and alcohols and derivatives thereof.

  Examples of glycols or derivatives thereof that give the polyester used in the present invention include 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1, other than ethylene glycol. Aliphatic dihydroxy compounds such as 5-pentanediol, 1,6-hexanediol and neopentyl glycol, polyoxyalkylene glycols such as diethylene glycol, polyethylene glycol, polypropylene glycol and polytetramethylene glycol, 1,4-cyclohexanedimethanol, spiro Examples thereof include alicyclic dihydroxy compounds such as glycol, aromatic dihydroxy compounds such as bisphenol A and bisphenol S, and derivatives thereof. Among these, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, and 1,4-cyclohexanedimethanol are preferably used in terms of moldability and handleability.

  In addition to terephthalic acid, the dicarboxylic acid or derivative thereof that provides the polyester used in the present invention includes isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenoxyethanedicarboxylic acid. Acids, aromatic dicarboxylic acids such as 5-sodiumsulfone dicarboxylic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, dimer acid, maleic acid, fumaric acid and other aliphatic dicarboxylic acids, 1,4-cyclohexanedicarboxylic acid, etc. Alicyclic dicarboxylic acids, oxycarboxylic acids such as paraoxybenzoic acid, and derivatives thereof. Examples of dicarboxylic acid derivatives include dimethyl terephthalate, diethyl terephthalate, 2-hydroxyethyl methyl terephthalate, dimethyl 2,6-naphthalenedicarboxylate, dimethyl isophthalate, dimethyl adipate, diethyl maleate, and dimethyl dimer. An esterified product can be mentioned. Among these, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and esterified products thereof are preferably used from the viewpoint of moldability and handleability.

  The biaxially oriented polyester film for molding of the present invention is required to have a 100% elongation stress (F100 value) in the longitudinal direction and the width direction at 150 ° C. of 5 MPa or more and 60 MPa or less, respectively, from the viewpoint of moldability. Examples of the molding method of the molded member include heat molding methods such as vacuum molding, pressure molding, vacuum pressure molding, press molding, plug assist molding, and any of these molding methods increases the temperature of the film by a preheating process using an infrared heater or the like. It has the process shape | molded after making it into a state. For this reason, it becomes possible to shape | mold into a complicated shape by reducing the molding stress at high temperature. For this reason, it is important that the stress at 100% elongation at 150 ° C. (F100 value) is 5 MPa or more and 60 MPa or less. If the F100 value is less than 5 MPa, it may not be able to withstand the tension for film transfer in the preheating step in the molding process, and the film may be deformed or broken in some cases. It becomes an unbearable film. On the other hand, when it exceeds 60 MPa, deformation during thermoforming is insufficient, and it becomes difficult to mold into a complicated shape. From the viewpoint of handleability and moldability, the 100% elongation stress (F100 value) in the film longitudinal direction and width direction at 150 ° C. is preferably from 10 MPa to 50 MPa, and most preferably from 15 MPa to 45 MPa. In particular, when used in a complicated shape, the stress at 100% elongation (F100 value) in the film longitudinal direction and width direction at 150 ° C. is preferably 5 MPa or more and 36 MPa or less.

  In addition, the biaxially oriented polyester film for molding of the present invention is preferably 100% or more and 500% or less in breaking direction in the film longitudinal direction and width direction at 150 ° C. in order to be molded into a more complicated shape. . Even when it is molded into a complicated shape, it can follow a high molding processing magnification, and can be excellent in economic efficiency and heat resistance. In terms of moldability, heat resistance, and economy, the elongation in the longitudinal direction and the width direction is preferably 100% or more and 400% or less, and most preferably 120% or more and 300% or less. In particular, when used in applications that require dimensional stability, the elongation in the longitudinal direction or width direction of the film is preferably 120% or more and 200% or less.

  In the biaxially oriented polyester film for molding of the present invention, examples of a method for setting the stress at 100% elongation at 150 ° C. and the elongation at break in the above ranges include, for example, a structural unit derived from neopentyl glycol for the polyester used. , 4-cyclohexanedimethanol-derived structural unit, isophthalic acid-derived structural unit, or 2,6-naphthalenedicarboxylic acid-derived structural unit. Such a structural unit suppresses orientational crystallization of the film at the time of molding, so that the stress at 100% elongation (F100 value) of the film at 150 ° C. can be kept low, and the elongation at break can also be improved. . As a preferable concentration, the structural unit derived from isophthalic acid and / or the structural unit derived from 2,6-naphthalenedicarboxylic acid with respect to the dicarboxylic acid component in the film is from 5 mol% to 15 mol%, or 1 to the glycol component. The structural unit derived from 1,4-cyclohexanedimethanol and / or the structural unit derived from neopentyl glycol may be 5 mol% or more and 15 mol% or less.

Molding the biaxially oriented polyester film of the present invention from the viewpoint of dimensional stability during processing, storage elastic modulus at 80 ° C. is not more than 2001MPa or more on 3000 MPa. If the storage elastic modulus at 80 ° C. is less than 2001 MPa, the dimensional stability in processing steps such as printing, vapor deposition, coating, and laminating decreases. Conversely, when the storage elastic modulus is greater than 4000 MPa, the dimensional stability is excellent, but the moldability may be deteriorated, which is not preferable.

  In order to increase the 100% elongation stress (F100 value) in the film longitudinal direction and the width direction at 150 ° C. in order to improve the moldability to 5 MPa or more and 60 MPa or less, a structural unit derived from neopentyl glycol as the polyester to be used, 1 , 4-cyclohexanedimethanol-derived structural unit, isophthalic acid-derived structural unit, or 2,6-naphthalenedicarboxylic acid-derived structural unit is preferably contained. It will decline. That is, moldability and dimensional stability are usually contradictory properties, and it was very difficult to achieve both. In the present invention, the 100% elongation stress (F100 value) in the film longitudinal direction and the width direction at 150 ° C. is 5 MPa or more and 60 MPa or less, and the storage elastic modulus at 80 ° C. is 2001 MPa or more and 4000 MPa or less. Has succeeded in achieving both stability and dimensional stability.

  In the biaxially oriented polyester film for molding of the present invention, as a method for setting the storage elastic modulus at 80 ° C. in the above range, for example, a method of setting the peak temperature of loss tangent to 100 ° C. or higher and 120 ° C. or lower is preferably used. By setting the loss tangent peak temperature within the above range, it is possible to control the storage elastic modulus at 80 ° C. to be 2001 MPa or more and 3500 MPa or less while maintaining the moldability. The loss tangent peak is based on the glass transition of the polymer. If the loss tangent peak temperature is less than 100 ° C., the storage elastic modulus at 80 ° C. may be less than 2001 MPa, and the dimensional stability decreases. End up. On the other hand, if the peak temperature of the loss tangent is to be made higher than 120 ° C., the 100% elongation stress (F100 value) in the film longitudinal direction and the width direction at 150 ° C. may be larger than 60 MPa, and the moldability is lowered. End up. A more preferable range of the loss tangent is 100 ° C. or higher and 115 ° C. or lower.

  In addition, the biaxially oriented polyester film for molding of the present invention has a storage elastic modulus of 1001 MPa or more and 3000 MPa or less in the film longitudinal direction and width direction at 100 ° C. in order to further improve the dimensional stability during processing. Is preferred. More preferably, it is 1050 MPa or more and 2500 MPa or less, and most preferably 1100 MPa or more and 2000 MPa or less. By setting the storage elastic modulus in the film longitudinal direction and width direction at 100 ° C. within the above ranges, the dimensional stability during processing can be further improved, and the processing temperature region is widened, which is very preferable.

  In the biaxially oriented polyester film for molding of the present invention, the method for setting the storage elastic modulus at 100 ° C. in the above range is not particularly limited, but, for example, the loss tangent peak temperature is 105 ° C. or more and 120 ° C. or less. Is preferably used, and more preferably 105 ° C. or higher and 110 ° C. or lower.

  As a method for controlling the peak temperature of loss tangent, it is preferable to increase the draw ratio. The stretching ratio is preferably 10 times or more in terms of surface magnification, more preferably 11 times or more, and most preferably 12 times or more. Further, it is preferable to lower the stretching temperature to such an extent that uneven stretching does not occur. In particular, in sequential biaxial stretching in which stretching in the width direction is performed after stretching in the longitudinal direction, a method of lowering the stretching temperature in the longitudinal direction, specifically, a method of 80 ° C. to 90 ° C. is preferable, and the stretching temperature in the width direction is preferred. Is preferably 90 ° C to 100 ° C, which is higher than the stretching temperature in the longitudinal direction.

  Further, it is preferable to include a structural unit derived from 2,6-naphthalenedicarboxylic acid having a rigid structure or 1,4-cyclohexanedimethanol having a ring structure. In the film, as a dicarboxylic acid component, The structural unit derived from 2,6-naphthalenedicarboxylic acid is 5 mol% or more and 15 mol% or less, or the structural unit derived from 1,4-cyclohexanedimethanol as a glycol component is contained 5 mol% or more and 15 mol% or less. Is preferred. On the other hand, components having many methylene groups that are flexible, such as 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1 , 6-hexanediol, succinic acid, adipic acid, sebacic acid, dimer acid and the like lower the peak temperature of loss tangent, so the content is preferably 5 mol% or less, and if it is 3 mol% or less Further preferred.

  Moreover, it is preferable that the biaxially oriented polyester film for molding of the present invention is a laminated polyester film having a polyester A layer and a polyester B layer. It is because the function by each layer can be provided by setting it as the laminated polyester film which has a polyester A layer and a polyester B layer. For example, by providing dimensional stability with the polyester A layer and providing moldability with the polyester B layer, it is possible to achieve both dimensional stability and moldability, which are the objects of the present invention.

  Moreover, when it is set as the laminated polyester film which has a polyester A layer and a polyester B layer, the surface orientation coefficient of a polyester A layer shall be 0.14 or more and 0.17 or less, melting | fusing point (TmA) of a polyester A layer, and melting | fusing point of a polyester B layer It is also very preferable that the difference (TmB−TmB) in (TmB) is 7 ° C. or more and 15 ° C. or less. By setting the plane orientation coefficient of the polyester A layer to 0.14 or more and 0.17 or less, dimensional stability can be ensured, and the melting point of the polyester B layer has a lower melting point than that of the polyester A layer. Can be achieved. At this time, from the viewpoint of moldability, dimensional stability, and interlayer adhesion between the A layer and the B layer, the difference between the melting point (TmA) of the polyester A layer and the melting point (TmB) of the polyester B layer (TmA-TmB). Is preferably 7 ° C. or more and 15 ° C. or less.

  From the viewpoint of moldability and dimensional stability, the plane orientation coefficient of the polyester A layer is more preferably from 0.145 to 0.165, and most preferably from 0.149 to 0.165.

The polyester A layer has a melting point (TmA) of 250 ° C. or more and 255 ° C. or less and a density of 1.380 g / cm ³ or more and 1.400 g / cm ³ or less from the viewpoint of heat resistance and dimensional stability. Is preferred. In order to set the melting point and density of the polyester A layer within such ranges, the polyester A layer may contain 95 to 99 mol% of structural units derived from ethylene glycol, or a structure derived from 1,4-cyclohexanedimethanol. It is preferable to contain 1 mol% or more and less than 5 mol% of the unit. In order to make the melting point and density of the polyester A layer within such ranges, the structural unit derived from ethylene glycol is contained in the polyester A layer by 95 mol% or more and less than 99 mol%, and derived from 1,4-cyclohexanedimethanol. It is particularly preferable that the structural unit is contained in an amount of 1 mol% or more and less than 5 mol%. Moreover, it is preferable to contain 95 mol% or more and 100 mol% or less of the structural unit derived from a terephthalic acid in the polyester A layer with respect to the structural unit derived from dicarboxylic acid (a dicarboxylic acid ester is included).

The polyester B layer has a melting point (TmB) of 235 ° C. or more and 245 ° C. or less and a density of 1.350 g / cm ³ or more and 1.365 g / cm ³ or less from the viewpoint of moldability. preferable. In order to set the melting point and density of the polyester B layer in such a range, the polyester B layer contains a structural unit derived from ethylene glycol of 85 mol% or more and less than 90 mol%, or a structure derived from 1,4-cyclohexanedimethanol. It is preferable to contain 10 mol% or more and less than 15 mol% of the unit. In order to set the melting point and density of the polyester B layer to such ranges, the structural unit derived from ethylene glycol is contained in the polyester B layer in an amount of 85 mol% or more and less than 90 mol%, and derived from 1,4-cyclohexanedimethanol. It is particularly preferable that the structural unit is contained in an amount of 10 mol% or more and less than 15 mol%. Moreover, it is preferable to contain 95 mol% or more and 100 mol% or less of the structural unit derived from terephthalic acid in the polyester B layer with respect to the structural unit derived from dicarboxylic acid (including dicarboxylic acid ester).

  By adopting such a configuration, it is excellent in moldability, dimensional stability, and heat resistance, and also in excellent interlaminar adhesion between the A layer and the B layer after high-magnification molding.

  When it is set as a laminated structure, it is preferable that a polyester A layer is located in at least one outermost layer especially from a viewpoint of dimensional stability.

  Moreover, when setting it as a laminated structure, from the viewpoint of moldability and dimensional stability, the lamination ratio H (−) of the A layer: (the thickness of the A layer) / (the thickness of the entire film) is 0.05 to 0.4. Preferably there is.

  Further, the biaxially oriented polyester film for molding of the present invention needs to have a storage elastic modulus in the film longitudinal direction and width direction at 180 ° C. of 41 MPa or more and 400 MPa or less from the viewpoint of heat resistance. If the storage elastic modulus at 180 ° C. is less than 41 MPa, the heat resistance is lowered, and the quality such as roughening of the film surface may be deteriorated during molding. Conversely, if the storage elastic modulus is greater than 400 MPa, the moldability may be deteriorated, which is not preferable. From the viewpoint of heat resistance and moldability, the storage elastic modulus in the film longitudinal direction and the width direction at 180 ° C. is more preferably from 100 MPa to 300 MPa, and most preferably from 130 MPa to 250 MPa.

  As a method for setting the storage elastic modulus in the film longitudinal direction and the width direction at 180 ° C. to 41 MPa or more and 400 MPa or less, for example, the melting point of the polyester film is preferably 220 ° C. or more. From the viewpoint of heat resistance and moldability, the melting point of the polyester film is preferably 230 ° C. or higher and 255 ° C. or lower, and most preferably 235 ° C. or higher and 245 ° C. or lower. Moreover, when setting it as a laminated structure, it is preferable that melting | fusing point (TmA) of a polyester A layer shall be 250 degreeC or more and 255 degrees C or less. Further, the melting point (TmB) of the polyester B layer is preferably 230 ° C. or higher and 245 ° C. or lower.

In order to satisfy moldability, dimensional stability, and heat resistance, a laminated polyester film having a polyester A layer and a polyester B layer, wherein the polyester A layer is a structural unit derived from ethylene glycol and a structural unit derived from diol. In contrast, 95 mol% or more and less than 99 mol%, containing 1 to 4 mol% of structural units derived from 1,4-cyclohexanedimethanol,
The structural unit derived from ethylene glycol in the polyester B layer is 85 mol% or more and less than 90 mol%, and the structural unit derived from 1,4-cyclohexanedimethanol is 10 mol% or more and 15 mol% based on the structural unit derived from diol. It is preferable to contain less than. Furthermore, the polyester A layer contains 1 mol% or more and less than 5 mol% of structural units derived from 1,4-cyclohexanedimethanol, and the polyester B layer contains 10 mol% or more of structural units derived from 1,4-cyclohexanedimethanol. A configuration in which the content is less than mol% and the melting point of the film (in the case of a laminated film, the melting point of the polyester B layer) is 235 ° C. or more and 245 ° C. or less is a very preferable embodiment. In such a configuration, in order to set the melting point of the film (the melting point of the polyester B layer in the case of a laminated film) to 235 ° C. or more and 245 ° C. or less, as the polyester B layer, a polyethylene terephthalate resin and 1,4-cyclohexanedi A method of mixing a methanol copolymerized polyethylene terephthalate resin in an extruder is preferably used. At that time, the copolymerization amount of 1,4-cyclohexanedimethanol in the 1,4-cyclohexanedimethanol copolymerized polyethylene terephthalate resin is preferably 25 mol% or more and 35 mol% or less. When the copolymerization amount is used with a resin in the above range, an appropriate transesterification reaction proceeds, and the melting point of the film (in the case of a laminated film, the melting point of the polyester B layer) may be 235 ° C. or higher and 245 ° C. or lower. It becomes possible. Further, the residence time in the extruder of the polyester resin of the polyester B layer is preferably 5 minutes or more and 15 minutes or less.

Here, the melting point of the polyester film is an endothermic peak temperature expressed by a melting phenomenon when measured at a heating rate of 20 ° C./min using a differential scanning calorimeter (DSC) (details will be described later). . When a polyester resin having a different composition is blended and used as a film, an endothermic peak due to multiple melting may appear. In that case, the endothermic peak temperature appearing at the highest temperature is set to the temperature of the polyester film of the present invention. The melting point.
The biaxially oriented polyester film for molding of the present invention preferably has a color tone b value of −1.5 or more and 1.5 or less from the viewpoint of the appearance after molding. When the color tone b value is smaller than −1.5, the appearance of the molded body using the biaxially oriented polyester film for molding of the present invention becomes bluish and the appearance is impaired. On the other hand, when the color tone b value is larger than 1.5, the appearance becomes yellowish and the appearance is deteriorated. More preferably, the color tone b value is from 0 to 1.5, most preferably from 0 to 1.2. Here, the color tone b value is a value obtained by transmission measurement based on JIS Z-8722-2000 for measuring the b value in the Lab color system. The method for adjusting the color tone b value to be not less than -1.5 and not more than 1.5 is not particularly limited, but the resin temperature during extrusion when producing the biaxially oriented polyester film for molding of the present invention is controlled to 275 ° C to 295 ° C. It is preferable to do. Since the resin temperature at the time of extrusion may become higher than the extruder temperature due to shear heat generation of the resin, it is necessary to set the extruder temperature from the resin kneading time, resin viscosity, and the like. Further, it is preferable that the inside of the extruder is an inert gas, preferably a flowing nitrogen atmosphere, and the oxygen concentration inside the supply unit is 0.7 vol% or less, more preferably 0.5 vol% or less. From the viewpoint of moldability and dimensional stability, the biaxially oriented polyester film for molding of the present invention has a stress at 100% elongation in the film longitudinal direction and the width direction at 150 ° C., and the storage elastic modulus in the film longitudinal direction and the width direction at 80 ° C. The storage modulus in the film longitudinal direction and the width direction at 180 ° C. is in a specific range. As described above, the film composition is a structural unit derived from neopentyl glycol, a structural unit derived from 1,4-cyclohexanedimethanol, and isophthalic acid. It is preferable to contain a structural unit derived from a structural unit derived from 2,6-naphthalenedicarboxylic acid, but by including these components, the heat resistance of extrusion may be lowered, so the resin temperature during extrusion, The oxygen concentration is important. Moreover, the color tone b value can be set to -1.5 or more and 1.5 or less by employ | adopting above-described extrusion temperature and oxygen concentration. In order to control the moldability, dimensional stability, and color tone, it is also effective to set the heat treatment temperature after biaxial stretching to a specific range in the production process of the biaxially oriented polyester film for molding of the present invention. . From the viewpoint of moldability and dimensional stability, it is effective to set the heat treatment temperature to a high temperature for a long time. However, if the heat treatment temperature is a high temperature for a long time, the color tone b value is in the range of −1.5 to 1.5. May fall off For this reason, a multi-stage heat treatment method in which heat treatment is performed again at a high temperature and in a short time and then heat treatment at a low temperature is preferable. In this case, the preferable high-temperature heat treatment temperature is 200 ° C. to 240 ° C., and more preferably 215 to 230 ° C. The high temperature heat treatment time is preferably 10 seconds to 40 seconds, and more preferably 15 seconds to 30 seconds. Further, the low temperature heat treatment temperature after the high temperature heat treatment is preferably 120 ° C. to 180 ° C., and the low temperature heat treatment temperature is preferably 5 seconds to 15 seconds. Further, a method of performing an annealing treatment offline after producing a film by performing a heat treatment at a high temperature for a short time is also very effective.

  In order to improve the dimensional stability after molding, the biaxially oriented polyester film for molding of the present invention preferably has a thermal shrinkage rate of 150% at 1 ° C. in the longitudinal direction and the width direction. In order to improve the dimensional stability after molding, it is preferable that the thermal shrinkage rate in the longitudinal direction and the width direction at 150 ° C. is −1% or more. Here, the heat shrinkage rate in the longitudinal direction and the width direction at 150 ° C. means that a film is cut into a rectangle 150 mm long × 10 mm wide in the longitudinal direction and the width direction, and marked lines are drawn on the sample at intervals of 100 mm. Is the rate of change in the distance between the marked lines before and after the heat treatment is performed by installing in a hot air oven heated to 150 ° C. for 30 minutes.

  Since both the longitudinal direction and the width direction have a heat shrinkage rate at 150 ° C. of −1% or more, or 1% or less, deformation or the like when a molded member after film molding is heated can be suppressed. Highly preferred.

  Examples of a method for adjusting the thermal shrinkage in the longitudinal direction and the width direction at 150 ° C. to −1% or more and 1% or less include a method of adjusting the heat treatment conditions of the film after biaxial stretching. When the treatment temperature is high, orientation relaxation occurs and the thermal shrinkage tends to be reduced, but the heat treatment temperature after biaxial stretching is 200 ° C. to 240 ° C. from the viewpoint of dimensional stability and film quality. It is preferable if it is 210 ° C to 235 ° C, more preferably 215 ° C to 230 ° C. In addition, the heat processing temperature of the biaxially oriented polyester film for molding of the present invention is caused by thermal history in a DSC curve when measured at a heating rate of 20 ° C./min in a nitrogen atmosphere in a differential scanning calorimeter (DSC). It can be determined from the minute endothermic peak.

  Moreover, as preferable heat processing time, although it can set arbitrarily in 5 to 60 second, it is preferable to set it as 10 to 40 second from a viewpoint of a moldability, dimensional stability, a color tone, and productivity, and 15-30. Preferably it is seconds. Further, the heat treatment is preferably performed while relaxing in the longitudinal direction and / or the width direction, since the heat shrinkage rate can be reduced. A preferable relaxation rate (relaxation rate) at the time of heat treatment is 3% or more. From the viewpoint of dimensional stability and productivity, 3% to 10% is preferable, and 3% to 5% is most preferable. preferable.

  Also, a method of heat treatment under two or more conditions is very preferable. After the heat treatment at a high temperature of 200 ° C. to 245 ° C., the heat shrinkage can be further reduced by performing the heat treatment at a temperature lower than the heat treatment temperature while relaxing in the longitudinal direction and / or the width direction. The heat treatment temperature in the second stage at this time is preferably 120 ° C. to 180 ° C., more preferably 150 ° C. to 180 ° C.

  Further, as a method for further reducing the thermal shrinkage rate, off-annealing treatment can be mentioned. That is, it is a method in which the polyester film once wound is subjected to heat treatment again.

  The thermal contraction rate at 150 ° C. is more preferably 0.8% or less, and most preferably 0.5% or less.

In order to improve the dimensional stability after molding, the biaxially oriented polyester film for molding of the present invention is at least when heated at a heating rate of 5 ° C./min from 25 ° C. to 220 ° C. under a load of 19.6 mN. It is preferable that the thermal deformation rate of the film at 150 ° C. in one direction is 0 to + 3%. By satisfying these characteristics, it is possible to suppress deformation of the film when stored under heating conditions after film formation, for example, preventing the occurrence of defects such as insert molding, warpage of in-mold molded products, and film peeling from the resin. (The dimensional stability after molding can be evaluated by, for example, [Example] (21) Dimensional stability after molding 1).
In order to improve the dimensional stability after molding, the off-annealing treatment is very effective as described above, but the off-annealing treatment temperature is set to 140 ° C. or more and less than 160 ° C., and the width direction is free, that is, the film Is not restricted in the film width direction, the thermal deformation rate in the width direction can be set in the above range, and the winding speed in the longitudinal direction is +0.5 to 5% from the unwinding speed. By lowering, it is possible to make the thermal deformation rate in the longitudinal direction within the above range. Furthermore, it is preferable to provide a stepwise cooling zone after the off-annealing treatment because the thermal contraction rate can be further reduced. More preferably, when the load is 19.6 mN and the temperature is increased from 25 ° C. to 220 ° C. at a rate of temperature increase of 5 ° C./min, the thermal deformation rate of the film at 150 ° C. in the longitudinal and width directions is 0 to + 3%. It is most preferable if the thermal deformation rate of the film at 150 ° C. in the longitudinal direction and the width direction is +0.5 to + 2%.

  In addition, the biaxially oriented polyester film for molding of the present invention has a load of 19.6 mN and a heating rate of 5 ° C./min from 25 ° C. to 220 ° C. when it is developed for applications in which dimensional stability after molding is particularly severe. It is preferable that the thermal deformation rate of the film at 180 ° C. in at least one direction when the temperature is raised is 0 to + 3%. More preferably, when the load is 19.6 mN and the temperature is increased from 25 ° C. to 220 ° C. at a rate of temperature increase of 5 ° C./min, the thermal deformation rate of the film at 150 ° C. in the longitudinal and width directions is 0 to + 3%. It is most preferable if the thermal deformation rate of the film at 180 ° C. in the longitudinal direction and the width direction is +0.5 to + 2%. By satisfying these characteristics, it is possible to suppress deformation of the film when stored under high-temperature heating conditions after film molding. For example, the occurrence of defects such as warpage of insert molding, in-mold molded product, and film peeling from the resin. (The dimensional stability after molding can be evaluated by, for example, [Example] (22) Dimensional stability after molding 2).

  In order to achieve the above thermal deformation rate, the off-annealing treatment temperature is set to 160 ° C. or more and 180 ° C. or less, and the width direction is in a free state, that is, the film is not restrained in the film width direction. It is possible to make the thermal deformation rate of the above range within the above range, and by reducing the longitudinal winding rate by 0.5 to 5% from the unwinding rate, the longitudinal thermal deformation rate is set to the above range. Is possible. Furthermore, it is preferable to provide a stepwise cooling zone after the off-annealing treatment because the thermal contraction rate can be further reduced. More preferably, the film has a thermal deformation rate of 0 to + 3% at 180 ° C. in the longitudinal direction and the width direction when the temperature is increased from 25 ° C. to 220 ° C. at a rate of temperature increase of 5 ° C./min with a load of 19.6 mN. It is most preferable if the thermal deformation rate of the film at 180 ° C. in the longitudinal direction and the width direction is +0.5 to + 2%.

The biaxially oriented polyester film for molding of the present invention preferably has a birefringence (Δn) of less than 20 × 10 ⁻³ from the viewpoint of uniform moldability. Here, uniform moldability means that the anisotropy of the film is small and the difference in the degree of molding is small depending on the direction. Birefringence is a numerical value defined by the refractive index of the film measured with an Abbe refractometer or the like, where n _{MD is} the refractive index in the longitudinal direction of the film, and n _TD is the refractive index in the width direction. Δn = | n _MD −n _TD | A birefringence of 20 × 10 ⁻³ or more is not preferable because the orientation balance in the plane direction of the film is poor, and the moldability may be deteriorated due to the influence of the high orientation direction. In order to further improve the uniform moldability, it is more preferably less than 15 × 10 ^{−3 and} most preferably less than 10 × 10 ⁻³ . In order to make birefringence into said range, it can achieve by adjusting a draw ratio, for example. In the case of the biaxial stretching method, birefringence can be reduced by bringing the stretching ratios in the longitudinal direction and the width direction close to each other. For example, the stretching ratio in the longitudinal direction is 3 to 3.8 times, the stretching ratio in the width direction is 3 to 3.8 times, preferably the stretching ratio in the longitudinal direction is 3 to 3.5 times, and the stretching ratio in the width direction is It is preferably 3 to 3.5 times. In order to set the birefringence within the above range, the preheating temperature for transverse stretching is preferably 80 to 100 ° C, more preferably 85 to 95 ° C. The transverse stretching temperature is preferably 90 ° C. or higher and 120 ° C. or lower, more preferably 95 ° C. or higher and 110 ° C. or lower, and most preferably 90 ° C. or higher and 100 ° C. or lower.

  The biaxially oriented polyester film for molding of the present invention preferably has a haze of less than 0.01% / μm from the viewpoint of the design properties of the molded member after molding. It is preferable that the haze is less than 0.01% / μm because the design of the molded member is improved.

  Examples of the method of setting the haze to 0.01% / μm or less include a method of reducing the concentration of particles to be contained in order to improve the film transportability. The biaxially oriented polyester film for molding of the present invention can contain particles in the film in order to improve the transportability of the film. Here, the particles to be used are not particularly limited, but externally added particles are preferably used in terms of transportability and appearance. Examples of the external additive particles include wet and dry silica, colloidal silica, aluminum silicate, titanium oxide, calcium carbonate, calcium phosphate, barium sulfate, and aluminum oxide, and organic particles include styrene, silicone, acrylic acid, methacrylic acid, Particles containing polyesters, divinyl compounds and the like as constituent components can be used. Among them, it is preferable to use inorganic particles such as wet and dry silica and alumina, and particles containing styrene, silicone, acrylic acid, methacrylic acid, polyester, divinylbenzene and the like as constituent components. Further, these externally added particles may be used in combination of two or more. From the viewpoint of transportability and appearance, the content of particles in the film is preferably 0.001 to 0.02% by mass, more preferably 0.002 to 0.01% by mass, based on the entire film as 100% by mass. .

  As a method for reducing the particle concentration without reducing the transportability of the film, for example, a method of adding two or more layers having at least an A layer and a B layer and adding particles only to the A layer or the B layer can be mentioned. It is done. By adding particles only to the A layer or the B layer, the amount of particles added can be reduced, and haze can be reduced without deteriorating the handleability. In order to further improve the handleability, a mode in which particles are contained only in the A layer and the C layer as a three-layer constitution of A layer / B layer / C layer is very preferable.

  The lamination ratio H (−) (H (−) = (A layer thickness) (μm) / (total film thickness) (μm)) of the A layer is preferably 0.01 or more and 0.4 or less. An attempt to make the lamination ratio less than 0.01 is not preferable because the thickness of the layer A becomes too thin and uneven lamination may occur. On the other hand, when the lamination ratio is larger than 0.4, the haze may be increased because the particle content increases. The lamination ratio H (−) is preferably 0.02 or more and 0.3 or less, and most preferably 0.03 or more and 0.25 or less. Further, in the case of a three-layer structure of A / B / C, {(thickness of A layer) + (thickness of C layer)) / (thickness of the entire film) is similarly 0.01 or more and 0.4 or less. Is preferred. From the viewpoint of film formability, the laminated thickness of the A layer and the C layer is preferably the same. Said lamination thickness ratio can be achieved by adjusting the discharge amount when extruding the polyester A constituting the A layer and the polyester B constituting the B layer. The discharge amount can be appropriately adjusted depending on the number of rotations of the screw of the extruder, the number of rotations of the gear pump, the extrusion temperature, the viscosity of the polyester raw material, etc. when a gear pump is used. The film lamination ratio is determined by measuring the thickness of each layer by observing the cross section of the film with a scanning electron microscope, transmission electron microscope, optical microscope or the like at a magnification of 500 to 10,000 times. be able to.

  The biaxially oriented polyester film for molding of the present invention has a film thickness of preferably 25 μm or more and 500 μm or less, more preferably 50 μm or more and 300 μm or less, more preferably 75 μm or more, from the viewpoint of the depth and shape retention of the molded member. Most preferably, it is 250 μm or less.

  Next, although the example of the specific manufacturing method of the biaxially-oriented polyester film for shaping | molding of this invention is described, this invention is limited to the example which concerns and is not interpreted.

  When a laminated polyester film having a polyester A layer and a polyester B layer is used, first, as polyester A used for the polyester A layer, a polyethylene terephthalate resin (a) and a 1,4-cyclohexanedimethanol copolymer polyethylene terephthalate resin (b) Is measured at a predetermined rate. Moreover, as polyester B used for the polyester B layer, polyethylene terephthalate resin (c) and 1,4-cyclohexanedimethanol copolymerized polyethylene terephthalate resin (d) are weighed at a predetermined ratio.

  Then, the mixed polyester resin is supplied to a vent type twin screw extruder and melt extruded. At this time, it is preferable to control the resin temperature to 275 ° C. to 295 ° C. under an atmosphere of flowing nitrogen in the extruder, with an oxygen concentration of 0.7% by volume or less. Next, foreign matter is removed and the amount of extrusion is leveled through a filter and a gear pump, respectively, and discharged from the T die onto a cooling drum in a sheet form. At that time, an electrostatic application method in which a cooling drum and the resin are brought into close contact with each other by static electricity using an electrode applied with a high voltage, a casting method in which a water film is provided between the casting drum and the extruded polymer sheet, and the casting drum temperature is set to be equal to that of the polyester resin. The sheet-like polymer is brought into close contact with the casting drum, cooled and solidified by a method of sticking the extruded polymer at a glass transition point to (glass transition point−20 ° C.) or a combination of these methods, and unstretched. Get a film. Among these casting methods, when using polyester, a method of applying an electrostatic force is preferably used from the viewpoint of productivity and flatness.

  The film of the present invention needs to be a biaxially oriented film from the viewpoints of heat resistance and dimensional stability. The biaxially oriented film is obtained by stretching an unstretched film in the longitudinal direction and then stretching in the width direction, or by stretching in the width direction and then stretching in the longitudinal direction, or by the longitudinal direction of the film. It can be obtained by stretching by a simultaneous biaxial stretching method in which the width direction is stretched almost simultaneously.

  The stretching ratio in such a stretching method is preferably 3.0 times or more and 4.2 times, more preferably 3.0 times or more and 4.0 times or less, particularly preferably in each of the longitudinal direction and the width direction. 3.0 times or more and 3.8 times or less are adopted. The stretching speed is desirably 1,000% / min or more and 200,000% / min or less. The stretching temperature is preferably 70 ° C. or higher and 120 ° C. or lower in the longitudinal direction and 80 ° C. or higher and 120 ° C. or lower in the width direction. Further, the stretching may be performed a plurality of times in each direction.

  Furthermore, the film is heat-treated after biaxial stretching. The heat treatment can be performed by any conventionally known method such as in an oven or on a heated roll. This heat treatment is performed at a temperature of 120 ° C. or higher and below the melting point of the polyester, preferably 200 ° C. or higher and 240 ° C. or lower, more preferably 210 ° C. to 235 ° C., and even more preferably 215 ° C. to 230 ° C. Is most preferable. The heat treatment time can be arbitrarily set within a range not deteriorating the characteristics, and is preferably 5 seconds to 60 seconds, more preferably 10 seconds to 40 seconds, and most preferably 15 seconds to 30 seconds. Good. Further, the heat treatment may be performed by relaxing the film in the longitudinal direction and / or the width direction. Furthermore, in order to improve the adhesive force with various processed layers such as a printing layer, an adhesive, a vapor deposition layer, a hard coat layer, and a weathering layer, at least one surface can be subjected to corona treatment or an easy adhesion layer can be coated. As a method of providing the coating layer in-line in the film manufacturing process, at least uniaxially stretched film with a coating layer composition dispersed in water is uniformly applied using a metalling ring bar or gravure roll. Then, a method of drying the coating while stretching is preferable, and the thickness of the easy-adhesion layer is preferably 0.01 μm or more and 1 μm or less. Also, various additives such as antioxidants, heat stabilizers, ultraviolet absorbers, infrared absorbers, pigments, dyes, organic or inorganic particles, antistatic agents, nucleating agents, etc. may be added to the easy-adhesion layer. Good. The resin preferably used for the easy-adhesion layer is preferably at least one resin selected from an acrylic resin, a polyester resin, and a urethane resin from the viewpoint of adhesiveness and handleability. Among them, an acrylic resin is preferable because it is excellent in weather resistance, heat resistance, and moisture resistance. Furthermore, in order to improve the dimensional stability after molding, it is preferable to perform off-annealing at 140 to 180 ° C.

  The biaxially oriented polyester film for molding of the present invention preferably contains an antioxidant from the viewpoint of film quality. By containing the antioxidant, it is possible to suppress the oxidative decomposition in the drying step and the extrusion step of the polyester resin, and it is possible to prevent the deterioration of the quality due to the gel-like foreign matter. Although it does not specifically limit as a kind of antioxidant, For example, the antioxidant classified into hindered phenols, hydrazine, phosphites, etc. can be used conveniently. Among them, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 3,5-di-tert-butyl-4-hydroxy-benzylphosphonate-diethyl ester 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris (2,4-di-t-butylphenyl) phosphite, etc. Is preferably used.

  In addition, the biaxially oriented polyester film for molding of the present invention can impart weather resistance when used outdoors. Examples of a method for imparting weather resistance include a method of laminating a weather resistant layer. The weathering layer absorbs light energy with a wavelength of 350 nm or more and 360 nm or less, emits harmless heat energy, phosphorescence and fluorescence by very fast energy conversion, suppresses photoexcitation and photochemical reaction of impurities in the polymer, and whitens It is a layer having a function of preventing embrittlement, cracking, yellowing, etc., and is composed of, for example, a weather resistant resin layer or a layer in which various resin layers contain an ultraviolet absorber. In particular, it is preferable that the average transmittance of the film after the lamination in the wavelength range of 350 nm to 360 nm is 45% or less, preferably 30% or less, and more preferably 10% or less. The preferred thickness range of the weather resistant layer is 0.5 μm or more and 20 μm or less, more preferably 1 μm or more and 15 μm or less, and most preferably 2 μm or more and 10 μm or less. Moreover, the method of adding a weathering agent is also mentioned. Even when a weathering agent is added, the average transmittance of the film in the wavelength range of 350 nm to 360 nm is 45% or less, preferably 30% or less, more preferably 10% or less, as in the method of laminating the weathering layer. . The weathering agent to be used is not particularly limited, but benzophenone compounds, triazine compounds, benzotriazole compounds, salicylic acid compounds, salicylate compounds, cyanoacrylate compounds, nickel compounds, benzoxazinone compounds, cyclic iminos. An ester compound or the like can be preferably used. Among these, benzotriazole compounds, benzophenone compounds, and benzoxazinone compounds are preferably used, and benzoxazinone compounds are particularly preferably used from the viewpoint of dispersibility. These compounds can be used alone or in combination of two or more. Further, stabilizers such as HALS (Hindered Amine Light Stabilizer) and antioxidants can be used in combination, and it is particularly preferable to use a phosphorus-based antioxidant in combination. Examples of the benzotriazole-based compound include 2-2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol and 2- (2H-benzotriazole-2- Yl) -4- (1,1,3,3-tetramethylbutyl) phenol, 2- (2H-benzotriazol-2-yl) -4-methylphenol, 2- (2H-benzotriazol-2-yl) -4,6-di-t-butylphenol, 2- (2H-benzotriazol-2-yl) -4,6-di-t-amylphenol, 2- (2H-benzotriazol-2-yl) -4- t-butylphenol, 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 ', '- can be exemplified di -t- butyl phenyl) -5-chloro-benzotriazole, or the like. Examples of the benzophenone compounds include 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2,2 ′, 4,4 ′. -Tetrahydroxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid and the like can be mentioned. Examples of the benzoxazinone compounds include 2-p-nitrophenyl-3,1-benzoxazin-4-one, 2- (p-benzoylphenyl) -3,1-benzoxazin-4-one, 2- ( 2-naphthyl) -3,1-benzoxazin-4-one, 2,2'-p-phenylenebis (3,1-benzoxazin-4-one), 2,2 '-(2,6-naphthylene) Bis (3,1-benzoxazin-4-one) and the like can be exemplified. Furthermore, it is preferable to use a cyanoacrylate-based tetramer compound in combination with another ultraviolet absorber in terms of imparting excellent weather resistance. In this case, the cyanoacrylate-based tetramer compound is preferably contained in an amount of 0.05 to 2% by weight, more preferably 0.1 to 1.0% by weight. The cyanoacrylate-based tetramer compound is a compound based on a tetramer of cyanoacrylate. For example, 1,3-bis (2′cyano-3,3-diphenylacryloyloxy) -2,2-bis- (2 ′ cyano-3,3-diphenylacryloyloxymethylpropane). Here, the ultraviolet absorber used in combination with cyanoacrylate is preferably a benzoxazinone compound, particularly 2,2 ′-(1,4-phenylene) bis (4H-3,1-benzoxazin-4-one), The addition amount is preferably 0.3 to 1.5% by weight in the film.

  In addition, the biaxially oriented polyester film for molding of the present invention can be laminated with a hard coat layer when used for applications in which scratch resistance is particularly severe. The hard coat layer only needs to have high hardness, scratch resistance, and wear resistance, and may be composed of acrylic, urethane, melamine, organic silicate compound, silicone, metal oxide, etc. it can. In particular, an acrylic, particularly active ray curable acrylic composition, or a thermosetting acrylic composition is preferably used in terms of hardness and durability, as well as curability and productivity. In the present invention, the pencil hardness of the film after laminating the hard coat layer is preferably HB or more, more preferably H or more, and most preferably 2H or more.

  Moreover, when the biaxially oriented polyester film for molding of the present invention is used for metallic decoration, it is preferable to use a metal compound deposited on at least one side of the film. By vapor-depositing and using a metal compound, the appearance becomes metallic, and it can be used as an alternative to a molded part using a currently plated resin. Among these, it is more preferable to use a metal compound having a melting point of 150 ° C. or higher and 400 ° C. or lower by vapor deposition. It is preferable to use a metal having a melting point within the range because the polyester film can be molded at a temperature range, and the deposited metal layer can be molded, and the occurrence of defects in the deposited layer due to molding can be easily suppressed. A particularly preferable melting point of the metal compound is 150 ° C. or higher and 300 ° C. or lower. Although it does not specifically limit as a metal compound whose melting | fusing point is 150 degreeC or more and 400 degrees C or less, Indium (157 degreeC) and tin (232 degreeC) are preferable, and indium is used preferably especially at the point of metallic luster and a color tone. be able to. Further, as a method for producing a vapor deposition film, a vacuum vapor deposition method, an EB vapor deposition method, a sputtering method, an ion plating method, or the like can be used. In order to further improve the adhesion between the polyester film and the vapor deposition layer, the surface of the film may be pretreated by a method such as a corona discharge treatment or an anchor coating agent. The thickness of the deposited film is preferably 1 nm or more and 500 nm or less, and more preferably 3n or more and 300 nm or less. From the viewpoint of productivity, it is preferably 3 nm or more and 200 nm or less.

  Moreover, when the biaxially oriented polyester film for molding of the present invention is used on the surface of a molded member by printing, the appearance and design can be imparted. The printing method is not particularly limited, but gravure printing, offset printing, screen printing, and the like are preferably used. The thickness of the printing layer is preferably 1 nm or more and 20 μm or less.

  The biaxially oriented polyester film for molding of the present invention is preferably used for decorating a molded member, and is preferably used for, for example, in-mold molding and insert molding as a molding decoration method. The in-mold molding referred to here is a molding method in which a film itself is placed in a mold and molded into a desired shape with a resin pressure to be injected to obtain a molded decorative body. Also, insert molding is to create a film molded body to be installed in the mold by vacuum molding, pressure molding, vacuum pressure molding, press molding, plug assist molding, etc., and filling the shape with resin, This is a molding method for obtaining a molded decorative body. Since a more complicated shape can be obtained, the biaxially oriented polyester film for molding of the present invention is particularly preferably used for insert molding.

  Since the biaxially oriented polyester film for molding of the present invention has a low molding stress in the molding temperature range, various molding methods such as vacuum molding, pressure molding, vacuum pressure molding, in-mold molding molded by injection resin pressure, etc. Since the storage modulus in the processing temperature range is in a specific range, it has excellent dimensional stability in processing processes such as coating, laminating, printing, and vapor deposition. It can be decorated by other means, and since it has a high storage elastic modulus in a high temperature region, it has excellent heat resistance, excellent surface properties even after molding, and excellent color tone, so the appearance is good For example, it can be suitably used for decorating molded members such as building materials, mobile devices, electrical products, automobile parts, and gaming machine parts.

(1) Melting point, glass transition temperature Using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., RDC220), measurement and analysis were performed based on JIS K7121-1987 and JIS K7122-1987. Using 5 mg of the polyester film as a sample, the temperature at the top of the endothermic peak obtained from the DSC curve when the temperature was raised from 25 ° C. to 300 ° C. at 20 ° C./min was defined as the melting point. When a plurality of endothermic peaks exist, the temperature at the apex of the endothermic peak on the highest temperature side was taken as the melting point. Also, the specific heat change based on the transition from the glass state to the rubber state is read, and the straight line that is equidistant from the extended straight line of each baseline in the direction of the vertical axis (the axis indicating the heat flow) The midpoint glass transition temperature at the point where the curve intersects was determined and used as the glass transition temperature.

(2) Intrinsic viscosity of polyester The intrinsic viscosity of the polyester resin and the film was measured at 25 ° C. using an Ostwald viscometer after dissolving the polyester in orthochlorophenol.

(3) Composition of polyester A polyester resin and a film are dissolved in hexafluoroisopropanol (HFIP), and the content of each monomer residue component and by-product diethylene glycol can be quantified using ¹ H-NMR and ¹³ C-NMR. it can. In the case of a laminated film, the components constituting each layer can be collected and evaluated by scraping off each layer of the film according to the laminated thickness. In addition, about the film of this invention, the composition was computed by calculation from the mixing ratio at the time of film manufacture.

(4) Concentration of contained particles in film It is possible to evaluate whether particles are contained in the film by dissolving 10 g of the polyester film in 100 g of orthochlorophenol and centrifuging the particles from the polyester. The particle concentration is determined from the following.
(Particle concentration) = (particle mass) / (total film mass) × 100
In addition, about the film of this invention, it computed by calculating from the particle concentration in the particle master produced by adding particle | grains at the time of superposition | polymerization, and the particle master concentration in a film.

(5) Haze Based on JIS K 7105 (1985), film haze was measured using a haze meter (HGM-2GP manufactured by Suga Test Instruments Co., Ltd.). The measurement was performed at three arbitrary locations, and the average value was adopted. In addition, the haze in this invention shows the haze value with respect to film thickness.

(6) Film thickness, layer thickness The film was embedded in an epoxy resin, and the film cross section was cut out with a microtome. The cross section was observed with a transmission electron microscope (TEM H7100, manufactured by Hitachi, Ltd.) at a magnification of 5000 times to determine the film thickness and the thickness of the polyester layer.

(7) Plane orientation coefficient, birefringence Using a sodium D line (wavelength 589 nm) as a light source and using an Abbe refractometer, the refractive index (n _MD ) in the longitudinal direction of the film, the refractive index (n _TD ) in the width direction, and the thickness The refractive index (n _ZD ) in the direction was measured, and the plane orientation coefficient (fn) and birefringence (Δn) were calculated from the following formulas.
fn = (n _MD + n _TD ) / 2-n _ZD
Δn = | n _MD −n _TD |

(8) Stress at 100% elongation at 150 ° C. (F100 value)
The film was cut into a rectangular shape having a length of 150 mm and a width of 10 mm in the longitudinal direction and the width direction to obtain a sample. Using a tensile tester (Orientec Tensilon UCT-100), the tensile test was performed in the longitudinal direction and the width direction of the film at an initial tensile chuck distance of 50 mm and a tensile speed of 300 mm / min. For the measurement, a film sample was set in a constant temperature layer set in advance at 150 ° C., and a tensile test was performed after 90 seconds of preheating. Read the load applied to the film when the sample is stretched 100% (when the distance between chucks is 100 mm), and divide by the cross-sectional area (film thickness x 10 mm) of the sample before the test. F100 value). In addition, the measurement was performed 5 times for each sample and each direction, and the average value was evaluated.

(9) Tensile elongation at 150 ° C. Tensile tests were performed in the longitudinal direction and the width direction of the film in the same manner as in (8), and the elongation when the film was broken was defined as the respective elongation. In addition, the measurement was performed 5 times for each sample and each direction, and the average value was evaluated.

(10) Storage viscoelastic modulus, loss tangent The film was cut into a rectangle of length 60 mm × width 5 mm in the longitudinal direction and width direction to obtain a sample. Using a dynamic viscoelasticity measuring device (Seiko Instruments, DMS6100), storage elastic modulus (E ′) at 80 ° C., 100 ° C. and 180 ° C., and peak temperature of loss tangent were obtained under the following conditions. .

Frequency: 10 Hz, test length: 20 mm, minimum load: about 100 mN, amplitude: 10 μm,
Measurement temperature range: −50 ° C. to 200 ° C., heating rate: 5 ° C./min.

(11) Thermal contraction rate The film was cut into a rectangular shape with a length of 150 mm and a width of 10 mm in the longitudinal direction and the width direction, respectively. Marks were drawn on the sample at intervals of 100 mm, and a heat treatment was performed by placing in a hot air oven heated to 150 ° C. with a 3 g weight suspended for 30 minutes. The distance between the marked lines after the heat treatment was measured, and the thermal contraction rate was calculated from the change in the distance between the marked lines before and after heating by the following formula. For each film, five samples were carried out in the longitudinal direction and the width direction for each film, and the average value was evaluated.

  Thermal contraction rate (%) = {(distance between marked lines before heat treatment) − (distance between marked lines after heat treatment)} / (distance between marked lines before heat treatment) × 100.

(12) Thermal deformation rate The film was cut into a rectangular shape with a length of 50 mm and a width of 4 mm in the longitudinal direction and the width direction as a sample, and a thermomechanical analyzer (manufactured by Seiko Instruments, TMA EXSTAR6000) was used under the following conditions. The rate of change of the film length at each temperature when the temperature was raised was defined as the thermal deformation rate.

Test length: 15 mm, load: 19.6 mN, heating rate: 5 ° C./min,
Measurement temperature range: 25-220 ° C
Thermal deformation rate (%)
= [{Film length at target temperature (mm) -trial length (mm)} / trial length (mm)] × 100.

(13) Density Using a density gradient tube made from an aqueous sodium bromide solution maintained at 25 ° C., the film was impregnated for 12 hours at 25 ° C., and the density was measured according to the position reached. In addition, three samples were impregnated at each level, and the average value was adopted.

(14) b value Based on JIS Z 8722 (2000), each film using a spectroscopic color difference meter (SE-2000 manufactured by Nippon Denshoku Industries Co., Ltd., light source halogen lamp 12V4A, 0 ° to −45 ° spectroscopic method) The b value of was measured by the transmission method.

(15) Formability The polyester film of the present invention was heated using a far-infrared heater at 450 ° C. so that the surface temperature was 150 ° C. and heated to 60 ° C. (70 × 70 mm, high And vacuum / pressure formation (pressure: 0.2 Ma). Three types of square dies, R, 1 mm, 2 mm, and 3 mm were prepared for the edge portion, respectively, and vacuum / compression molding was performed. The state of being molded along the mold was evaluated according to the following criteria.
S: Molded with R1 mm (R1 mm could be reproduced).
A: Molding was possible at R2 mm (R2 mm could be reproduced), but molding was not possible at R1 mm.
B: R3 mm could be molded (R3 mm could be reproduced), but R2 mm could not be molded. C: Could not be molded with R3 mm.

(16) Uniform moldability In the tensile test carried out in (8), the difference between the absolute values of the F100 values in the film longitudinal direction and the width direction was evaluated as follows.
S: Difference in absolute value between F100 values in the film longitudinal direction and the width direction is less than 10 A: Difference in absolute value between F100 values in the film longitudinal direction and the width direction is 10 or more and less than 15 B: F100 in the film longitudinal direction and the width direction Difference in absolute value between 15 and less than 20 C: Difference in absolute value between F100 values in the film longitudinal direction and width direction is 20 or more.

(17) Film appearance Screen printing was performed on the film surface. Printing was performed using Mino Group's ink U-PET (517) and screen SX270T under the conditions of a squeegee speed of 300 mm / sec and a squeegee angle of 45 °, and then in a hot air oven at 70 ° C for 15 minutes. It dried and obtained the printing layer laminated | multilayer film. About the obtained printing layer laminated | multilayer film, the following reference | standard evaluated about the film external appearance from the opposite surface of a printing layer.
S: Appearance with clear printing and excellent design.
A: Although the printing was slightly hazy, the appearance was excellent in design.
B: Although printing was hazy, the designability was at a level with no problem.
C: Printing was unclear and the appearance was inferior.

(18) Dimensional stability 1
About the printing layer laminated film which performed screen printing and drying on the same conditions as (17), it evaluated on the following reference | standard evaluated by the following reference | standard about the film surface on the opposite surface of a printing layer.
S: The film surface was completely rough, no undulation was observed, and the surface property was excellent.
A: Slight undulation was observed on the film surface, but the surface property was excellent.
B: Waviness was observed on the film surface, but the surface property was at a level that is not a problem.
C: Roughness occurred on the film surface and the surface property was inferior.

(19) Dimensional stability 2
Screen printing was performed under the same conditions as in (17), and for the printed layer laminated film that was dried in a hot air oven at 80 ° C. for 15 minutes, the film surface opposite to the printed layer was evaluated according to the following criteria. went.
S: The film surface was completely rough, no undulation was observed, and the surface property was excellent.
A: Slight undulation was observed on the film surface, but the surface property was excellent.
B: Waviness was observed on the film surface, but the surface property was at a level that is not a problem.
C: Roughness occurred on the film surface and the surface property was inferior.

(20) The surface of the molded body molded with heat resistance (15) was evaluated according to the following criteria.
S: The surface of the molded body was completely rough, no waviness was observed, and the surface property was excellent.
A: Slight undulation was observed on the surface of the molded body, but the surface property was excellent.
B: Waviness was observed on the surface of the molded body, but the surface property was at a level that is not a problem.
C: Roughness occurred on the surface of the molded body and the surface property was inferior.

(21) Dimensional stability after molding 1
The molded body molded in (15) was set in an injection mold, and PC / ABS resin (SD polycarbonate IM6011) manufactured by Sumitomo Dow Co., Ltd. was injection molded at a molding temperature of 260 ° C. to perform insert molding. The obtained molded body was subjected to a heat test of 70 ° C. × 10 h, and evaluated according to the following criteria. A: No change was observed in the shape of the molded body.
B: Although the molded body warped toward the film side, it was at a level causing no problem in practical use.
C: The molded body warped to the film side, and peeling of the film occurred from the end of the molded body.

(22) Dimensional stability after molding 2
The molded body molded in (15) was set in an injection mold, and PC / ABS resin (SD polycarbonate IM6011) manufactured by Sumitomo Dow Co., Ltd. was injection molded at a molding temperature of 260 ° C. to perform insert molding. The obtained molded body was subjected to a heat resistance test at 80 ° C. × 10 h, and evaluated according to the following criteria. A: No change was observed in the shape of the molded body.
B: Although the molded body warped toward the film side, it was at a level causing no problem in practical use.
C: The molded body warped to the film side, and peeling of the film occurred from the end of the molded body.

(23) Weather resistance test A forced ultraviolet irradiation test was conducted under the following conditions using an ultraviolet deterioration accelerating tester iSuper UV Tester SUV-W131 (Iwasaki Electric Co., Ltd.).

Illuminance: 100 mW / cm ² , temperature: 60 ° C., relative humidity: 50% RH, irradiation time: 6 hours For films before and after the light resistance test, a spectroscopic color difference meter SE-2000 type (manufactured by Nippon Denshoku Industries Co., Ltd.) was used. The b value was measured by the transmission method according to JIS-K-7105, and the evaluation was performed according to the following criteria based on the amount of change in the b value.
A: Δb value is less than 4 B: Δb value is 4 or more (24) Interlayer adhesion In the same manner as in (8), a tensile test was performed 5 times each in the longitudinal direction and the width direction of the film, and the film was broken. Nitto Denko Co., Ltd. OPP adhesive tape (Damplon Ace No. 375) was bonded to both sides of the broken part, and the composition of OPP adhesive tape / film sample after tensile test / OPP adhesive tape was created. The tape was forcibly peeled by 180 °, the film sample after the tensile test was observed, and the evaluation was performed according to the following criteria.
A: No delamination occurred between the layers.
B: Peeling between the A layer / B layer occurred once or more.

(Manufacture of polyester)
The polyester resin used for film formation was prepared as follows.

(Polyester A)
Polyethylene terephthalate resin (inherent viscosity 0.65) in which the terephthalic component is 100 mol% as the dicarboxylic acid component, the ethylene glycol component is 98.8 mol%, and the diethylene glycol component is 1.2 mol% as the glycol component.

(Polyester B)
A copolymerized polyester (GN001, manufactured by Eastman Chemical Co.) in which 33 mol% of 1,4-cyclohexanedimethanol was copolymerized with respect to the glycol component was used as cyclohexanedimethanol copolymerized polyethylene terephthalate (inherent viscosity 0.75).

(Polyester C)
Neopentyl glycol copolymer polyethylene terephthalate having 100 mol% of terephthalic component as dicarboxylic acid component, 68.5 mol% of ethylene glycol component, 30 mol% of neopentyl glycol component and 1.5 mol% of diethylene glycol component as glycol component Resin (intrinsic viscosity 0.75).

(Polyester D)
Isophthalic acid copolymer polyethylene comprising 82.5 mol% of terephthalic component as dicarboxylic acid component, 17.5 mol% of isophthalic component, 98.5 mol% of ethylene glycol component and 1.5 mol% of diethylene glycol component as glycol components Terephthalate resin (intrinsic viscosity 0.7).

(Polyester E)
Polybutylene terephthalate resin (intrinsic viscosity 1.22) in which the terephthalic component is 100 mol% as the dicarboxylic acid component and the 1,4-butanediol component is 100 mol% as the glycol component.

(Particle Master A)
Polyethylene terephthalate particle master (intrinsic viscosity 0.65) containing polyester A with aggregated silica particles having an average particle size of 2.2 μm at a particle concentration of 2 mass%.

(Weatherproof master)
Polyester A prepared as described above and 2,2 ′-(1,4-phenylene) bis (4H-3,1benzoxazin-4-one) were mixed at a mass ratio of 95: 5, and vented biaxial Using an extruder, the mixture was kneaded at 280 ° C. to prepare a weathering agent master of 2,2 ′-(1,4-phenylene) bis (4H-3,1benzoxazin-4-one).

(Example 1)
Polyester A and polyester B are mixed at a mass ratio of 70:30 and supplied to a vented twin screw extruder having an oxygen concentration of 0.2% by volume, melted at 275 ° C. to remove foreign matter and level the amount of extrusion. After performing, it discharged in the sheet form on the cooling drum temperature-controlled at 25 degreeC from T die. At that time, a wire-like electrode having a diameter of 0.1 mm was applied electrostatically and adhered to the cooling drum to obtain an unstretched film.

  Next, before stretching in the longitudinal direction, the film temperature is raised with a heated roll, the preheating temperature is 85 ° C., the stretching temperature is 90 ° C., and the film is stretched 3 times in the longitudinal direction, and immediately controlled at 40 ° C. Cooled down.

Thereafter, a corona discharge treatment is performed, the wetting tension on both sides of the base film is set to 50 mN / m, and the following coating agents A, B, C, D, E, and F are mixed on the treated surface while ultrasonically dispersing. And # 4 metering bar.
A: Water-dispersed polyester resin (acid group 4.5 mg / g)
B: Methylolated melamine (diluent: isopropyl alcohol / water)
C: Oxazoline crosslinking agent (Nippon Shokubai "Epocross" WS-500
D: Colloidal silica (average particle size 140 nm)
E: Colloidal silica (average particle size 300 nm)
F: Fluorine-based surfactant (diluent: water)
Solid content mass ratio: A / B / C / D / E / F
= 100 parts by weight / 38 parts by weight / 5 parts by weight / 2 parts by weight / 0.5 parts by weight / 0.2 parts by weight Next, in a tenter type horizontal stretching machine, the preheating temperature is 95 ° C., the stretching temperature is 100 ° C., and the width direction is 3 The film was stretched 8 times and subjected to heat treatment at 230 ° C. for 5 seconds while relaxing 4% in the width direction in the tenter to obtain a biaxially oriented polyester film having a film thickness of 188 μm.

(Example 2)
The film of Example 1 is free in the width direction in a hot air oven at 150 ° C. (in a state where the film is not restrained in the film width direction), and the longitudinal winding speed is reduced by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.

(Example 3)
In the hot air oven at 180 ° C., the film of Example 1 is free in the width direction (in a state where the film is not restrained in the film width direction), and is turned off while lowering the winding speed in the longitudinal direction by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.

Example 4
A biaxial film having a film thickness of 188 μm was changed in the same manner as in Example 1 except that the composition and film configuration were changed as shown in the table, and the draw ratio in the longitudinal direction was 3.3 times and the draw ratio in the width direction was 3.7 times. An oriented polyester film was obtained.

(Example 5)
In the hot air oven at 150 ° C., the film of Example 4 was free in the width direction (in a state where the film was not restrained in the film width direction) and turned off while lowering the winding speed in the longitudinal direction by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.

(Example 6)
In the hot air oven at 180 ° C., the film of Example 4 is free in the width direction (in a state where the film is not restrained in the film width direction) and turned off while lowering the winding speed in the longitudinal direction by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.

(Example 7)
A biaxial film having a film thickness of 188 μm was changed in the same manner as in Example 1 except that the composition and film configuration were changed as shown in the table, and the draw ratio in the longitudinal direction was 3.3 times and the draw ratio in the width direction was 3.7 times. An oriented polyester film was obtained.

(Example 8)
In the hot air oven at 180 ° C., the film of Example 7 is free in the width direction (in a state where the film is not restrained in the film width direction) and turned off while lowering the winding speed in the longitudinal direction by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.

Example 9
A biaxial film having a film thickness of 188 μm was changed in the same manner as in Example 1 except that the composition and film configuration were changed as shown in the table, and the draw ratio in the longitudinal direction was 3.3 times and the draw ratio in the width direction was 3.7 times. An oriented polyester film was obtained.

(Example 10)
In the hot air oven at 150 ° C., the film of Example 9 is free in the width direction (in a state where the film is not restrained in the film width direction) and turned off while lowering the winding speed in the longitudinal direction by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.

(Example 11)
In the hot air oven at 180 ° C., the film of Example 9 is free in the width direction (in a state where the film is not restrained in the film width direction) and turned off while lowering the winding speed in the longitudinal direction by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.

(Example 12)
A biaxial film having a film thickness of 188 μm was changed in the same manner as in Example 1 except that the composition and film configuration were changed as shown in the table, and the draw ratio in the longitudinal direction was 3.3 times and the draw ratio in the width direction was 3.7 times. An oriented polyester film was obtained.

(Example 13)
In the hot air oven at 180 ° C., the film of Example 12 was free in the width direction (in a state where the film was not restrained in the film width direction) and turned off while lowering the winding speed in the longitudinal direction by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.

(Example 14)
A biaxial film having a film thickness of 188 μm was changed in the same manner as in Example 1 except that the composition and film configuration were changed as shown in the table, and the draw ratio in the longitudinal direction was 3.3 times and the draw ratio in the width direction was 3.7 times. An oriented polyester film was obtained.

(Example 15)
In the hot air oven at 180 ° C., the film of Example 14 was free in the width direction (in a state where the film was not restrained in the film width direction) and turned off while lowering the winding speed in the longitudinal direction by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.

(Example 16)
A biaxial film having a film thickness of 188 μm was changed in the same manner as in Example 1 except that the composition and film configuration were changed as shown in the table, and the draw ratio in the longitudinal direction was 3.3 times and the draw ratio in the width direction was 3.7 times. An oriented polyester film was obtained.

(Example 17)
The film of Example 16 was subjected to an off-annealing treatment in a hot air oven at 180 ° C. in a width direction free state (a state in which the film was not restrained in the film width direction) and a longitudinal winding tension was controlled, and a film thickness of 188 μm. A biaxially oriented polyester film was obtained.

(Example 18)
A biaxial film having a film thickness of 188 μm was changed in the same manner as in Example 1 except that the composition and film configuration were changed as shown in the table, and the draw ratio in the longitudinal direction was 3.3 times and the draw ratio in the width direction was 3.7 times. An oriented polyester film was obtained.

(Example 19)
The film of Example 16 was subjected to an off-annealing treatment in a hot air oven at 180 ° C. in a width direction free state (a state in which the film was not restrained in the film width direction) and a longitudinal winding tension was controlled, and a film thickness of 188 μm. A biaxially oriented polyester film was obtained.

(Example 20)
A biaxial film having a film thickness of 188 μm was changed in the same manner as in Example 1 except that the composition and film configuration were changed as shown in the table, and the draw ratio in the longitudinal direction was 3.3 times and the draw ratio in the width direction was 3.7 times. An oriented polyester film was obtained. Furthermore, the film obtained is free in the width direction in a 180 ° C hot air oven (the film is not constrained in the film width direction), and the longitudinal winding speed is reduced by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.

(Example 21)
A biaxial film having a film thickness of 188 μm was changed in the same manner as in Example 1 except that the composition and film configuration were changed as shown in the table, and the draw ratio in the longitudinal direction was 3.3 times and the draw ratio in the width direction was 3.7 times. An oriented polyester film was obtained. Furthermore, the film obtained is free in the width direction in a 180 ° C hot air oven (the film is not constrained in the film width direction), and the longitudinal winding speed is reduced by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.

(Example 22)
A biaxial film having a film thickness of 188 μm was changed in the same manner as in Example 1 except that the composition and film configuration were changed as shown in the table, and the draw ratio in the longitudinal direction was 3.3 times and the draw ratio in the width direction was 3.7 times. An oriented polyester film was obtained. Furthermore, the film obtained is free in the width direction in a 180 ° C hot air oven (the film is not constrained in the film width direction), and the longitudinal winding speed is reduced by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 125 μm.

(Example 23)
A biaxial film having a film thickness of 188 μm was changed in the same manner as in Example 1 except that the composition and film configuration were changed as shown in the table, and the draw ratio in the longitudinal direction was 3.3 times and the draw ratio in the width direction was 3.7 times. An oriented polyester film was obtained. Furthermore, the film obtained is free in the width direction in a 180 ° C hot air oven (the film is not constrained in the film width direction), and the longitudinal winding speed is reduced by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.

(Example 24)
A biaxial film having a film thickness of 188 μm was changed in the same manner as in Example 1 except that the composition and film configuration were changed as shown in the table, and the draw ratio in the longitudinal direction was 3.3 times and the draw ratio in the width direction was 3.7 times. An oriented polyester film was obtained.
(Example 25)
In the hot air oven at 180 ° C., the film of Example 24 was free in the width direction (in a state where the film was not restrained in the film width direction) and turned off while lowering the winding speed in the longitudinal direction by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.

(Example 26)
A biaxial film having a film thickness of 188 μm was changed in the same manner as in Example 1 except that the composition and film configuration were changed as shown in the table, and the draw ratio in the longitudinal direction was 3.3 times and the draw ratio in the width direction was 3.7 times. An oriented polyester film was obtained.
(Example 27)
The film of Example 26 was turned off in a hot air oven at 180 ° C. while being free in the width direction (in a state where the film was not restrained in the film width direction), and the longitudinal winding speed was reduced by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.
(Example 28)
A biaxial film having a film thickness of 188 μm was changed in the same manner as in Example 1 except that the composition and film configuration were changed as shown in the table, and the draw ratio in the longitudinal direction was 3.3 times and the draw ratio in the width direction was 3.7 times. An oriented polyester film was obtained.
(Example 29)
In the hot air oven at 180 ° C., the film of Example 28 was free in the width direction (in a state where the film was not restrained in the film width direction) and turned off while lowering the winding speed in the longitudinal direction by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.
(Example 30)
The composition and film configuration were changed as shown in the table, the oxygen concentration in the bent twin-screw extruder was 1% by volume, the extrusion temperature was 300 ° C., the stretch ratio in the longitudinal direction was 3.3 times, and the stretch ratio in the width direction was 3. A biaxially oriented polyester film having a film thickness of 188 μm was obtained in the same manner as in Example 1 except that the ratio was 7 times. Furthermore, the film obtained is free in the width direction in a 180 ° C hot air oven (the film is not constrained in the film width direction), and the longitudinal winding speed is reduced by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.
(Example 31)
A biaxial film having a film thickness of 188 μm was changed in the same manner as in Example 1 except that the composition and film configuration were changed as shown in the table, and the draw ratio in the longitudinal direction was 3.3 times and the draw ratio in the width direction was 3.7 times. An oriented polyester film was obtained.
(Example 32)
In the hot air oven at 180 ° C., the film of Example 31 is free in the width direction (in a state where the film is not restrained in the film width direction) and turned off while lowering the winding speed in the longitudinal direction by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.
(Example 33)
A biaxial film having a film thickness of 188 μm was changed in the same manner as in Example 1 except that the composition and film configuration were changed as shown in the table, and the draw ratio in the longitudinal direction was 3.3 times and the draw ratio in the width direction was 3.7 times. An oriented polyester film was obtained.
(Example 34)
In the hot air oven at 180 ° C., the film of Example 33 was free in the width direction (in a state where the film was not restrained in the film width direction), and turned off while lowering the winding speed in the longitudinal direction by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.
(Example 35)
A biaxial film having a film thickness of 188 μm was changed in the same manner as in Example 1 except that the composition and film configuration were changed as shown in the table, and the draw ratio in the longitudinal direction was 3.3 times and the draw ratio in the width direction was 3.7 times. An oriented polyester film was obtained.
(Example 36)
The film of Example 35 was turned off in a hot air oven at 180 ° C. while being free in the width direction (in a state where the film was not restrained in the film width direction) and the longitudinal winding speed being reduced by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.
(Example 37)
A biaxial film having a film thickness of 188 μm was changed in the same manner as in Example 1 except that the composition and film configuration were changed as shown in the table, and the draw ratio in the longitudinal direction was 3.3 times and the draw ratio in the width direction was 3.7 times. An oriented polyester film was obtained.
(Example 38)
In the hot air oven at 180 ° C., the film of Example 37 was free in the width direction (in a state where the film was not restrained in the film width direction) and turned off while lowering the winding speed in the longitudinal direction by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.
(Example 39)
A biaxial film having a film thickness of 188 μm was changed in the same manner as in Example 1 except that the composition and film configuration were changed as shown in the table, and the draw ratio in the longitudinal direction was 3.3 times and the draw ratio in the width direction was 3.7 times. An oriented polyester film was obtained.
(Example 40)
In the hot air oven at 180 ° C., the film of Example 39 was free in the width direction (in a state where the film was not restrained in the film width direction) and turned off while lowering the winding speed in the longitudinal direction by 1.5% from the unwinding speed. Annealing treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 188 μm.

(Comparative Example 1)
A biaxially oriented polyester film having a film thickness of 188 μm was obtained in the same manner as in Example 1 except that the composition and the film configuration were changed as shown in the table.

(Comparative Example 2)
A biaxial film having a film thickness of 188 μm was changed in the same manner as in Example 1 except that the composition and film configuration were changed as shown in the table, and the draw ratio in the longitudinal direction was 3.3 times and the draw ratio in the width direction was 3.7 times. An oriented polyester film was obtained.

(Comparative Example 3)
The composition and film configuration were changed as shown in the table, the oxygen concentration in the bent twin-screw extruder was 1% by volume, the extrusion temperature was 285 ° C., the draw ratio in the longitudinal direction was 3.3 times, and the draw ratio in the width direction was 3. A biaxially oriented polyester film having a film thickness of 188 μm was obtained in the same manner as in Example 1 except that the ratio was 7 times.

(Comparative Example 4)
The composition and film configuration were changed as shown in the table, the oxygen concentration in the bent twin-screw extruder was 1% by volume, the extrusion temperature was 300 ° C., the stretch ratio in the longitudinal direction was 3.3 times, and the stretch ratio in the width direction was 3. A biaxially oriented polyester film having a film thickness of 188 μm was obtained in the same manner as in Example 1 except that the ratio was 7 times.

The meanings of the abbreviations in the table are as follows.
EG: ethylene glycol CHDM: 1,4-cyclohexanedimethanol DEG: diethylene glycol NPG: neopentyl glycol TPA: terephthalic acid IPA: isophthalic acid

  Since the biaxially oriented polyester film for molding of the present invention has a low molding stress in the molding temperature range, various molding methods such as vacuum molding, pressure molding, vacuum pressure molding, in-mold molding molded by injection resin pressure, etc. Since the storage modulus in the processing temperature range is in a specific range, it has excellent dimensional stability in processing processes such as coating, laminating, printing, and vapor deposition. It can be decorated by other means, and since it has a high storage elastic modulus in a high temperature region, it has excellent heat resistance, excellent surface properties even after molding, and excellent color tone, so the appearance is good For example, it can be suitably used for decorating molded members such as building materials, mobile devices, electrical products, automobile parts, and gaming machine parts.

Claims (14)

The 100% elongation stress (F100 value) in the film longitudinal direction and the width direction at 150 ° C. is 5 MPa or more and 60 MPa or less, respectively, and the storage elastic modulus in the film longitudinal direction and the width direction at 80 ° C. is 2001 MPa or more and 3000 MPa or less, respectively. A biaxially oriented polyester film for molding whose storage elastic modulus in the film longitudinal direction and the width direction at 180 ° C. is from 41 MPa to 400 MPa.
The biaxially oriented polyester film for molding according to claim 1, wherein the color tone b value of the film is from -1.5 to 1.5. A laminated polyester film having a polyester A layer and a polyester B layer, wherein the surface orientation coefficient of the polyester A layer is from 0.14 to 0.17, the melting point (TmA) of the polyester A layer and the melting point of the polyester B layer ( The biaxially oriented polyester film for molding according to claim 1 or 2, wherein a difference in TmB) (TmA-TmB) is 7 ° C or higher and 15 ° C or lower, and a peak temperature of loss tangent is 100 ° C or higher and 120 ° C or lower. The melting point (TmA) of the polyester A layer is 250 ° C. or more and 255 ° C. or less, the density of the polyester A layer is 1.380 g / cm ³ or more and 1.400 g / cm ³ or less, and the melting point (TmB) of the polyester B layer is The biaxially oriented polyester film for molding according to claim ³ , wherein the polyester B layer has a density of 235 ° C to 245 ° C and a density of the polyester B layer of 1.350 g / cm ^{3 to} 1.365 g / cm ³ . The biaxially oriented polyester film for molding according to any one of claims 1 to 4, wherein a stress at 100% elongation (F100 value) in a film longitudinal direction and a width direction at 150 ° C is 5 MPa or more and 36 MPa or less, respectively. A laminated polyester film having a polyester A layer and a polyester B layer, wherein the polyester A layer contains 1 mol% or more and less than 5 mol% of a structural unit derived from 1,4-cyclohexanedimethanol,
The biaxially oriented polyester film for molding according to any one of claims 1 to 5, wherein the polyester B layer contains a structural unit derived from 1,4-cyclohexanedimethanol in an amount of 10 mol% to less than 15 mol%. The biaxially oriented polyester film for molding according to any one of claims 1 to 6, wherein the melting point of the film is from 235 ° C to 245 ° C. A laminated polyester film having a polyester A layer and a polyester B layer, wherein the polyester A layer has a structural unit derived from ethylene glycol of 95 mol% or more and less than 99 mol%, based on the structural unit derived from diol. -Containing 1 mol% or more and less than 5 mol% of structural units derived from cyclohexanedimethanol,
The structural unit derived from ethylene glycol in the polyester B layer is 85 mol% or more and less than 90 mol%, and the structural unit derived from 1,4-cyclohexanedimethanol is 10 mol% or more and 15 mol% based on the structural unit derived from diol. The biaxially oriented polyester film for molding according to any one of claims 1 to 7, which is contained in an amount of less. The polyester A layer contains a structural unit derived from terephthalic acid (including terephthalic acid ester) with respect to a structural unit derived from dicarboxylic acid (including a dicarboxylic acid ester) in a range of 95 mol% to 100 mol%.
The molding according to claim 8, wherein the polyester B layer contains a structural unit derived from terephthalic acid with respect to a structural unit derived from dicarboxylic acid (including a dicarboxylic acid ester) in a range of 95 mol% to 100 mol%. Biaxially oriented polyester film. A biaxially oriented polyester for molding according to any one of claims 1 to 9, which is a laminated polyester film having a polyester A layer and a polyester B layer, wherein the lamination ratio H (-) is 0.01 or more and 0.4 or less. the film. The biaxially oriented polyester film for molding according to any one of claims 1 to 10, which is a laminated polyester film having a polyester A layer and a polyester B layer, wherein the polyester A layer is located in at least one outermost layer. The biaxially oriented polyester film for molding according to any one of claims 1 to 11, wherein the thermal shrinkage in the longitudinal direction and the width direction at 150 ° C is from -1% to 1%. The thermal deformation rate of the film at 150 ° C in at least one direction when the temperature is increased from 25 ° C to 220 ° C at a temperature increase rate of 5 ° C / min with a load of 19.6 mN is 0 to + 3%. The biaxially oriented polyester film for molding according to any one of the above. The thermal deformation rate of the film at 180 ° C in at least one direction when heated from 25 ° C to 220 ° C at a heating rate of 5 ° C / min with a load of 19.6 mN is 0 to + 3%. The biaxially oriented polyester film for molding according to any one of the above.